Boston Marathon bombing suspect Dzhokhar Tsarnaev told authorities that his sister-in-law, Katherine Russell, played no role in the April 15 blasts, a federal law enforcement official said.

Russell has been under scrutiny since her husband Tamerlan Tsarnaev and his younger brother were accused of planning and carrying out the bombing that killed three people and wounded more than 200.

Authorities are still investigating whether Russell had any involvement.

Russell's lawyers said in a statement that she "plans to continue to meet with investigators, part of a series of meetings over many hours where she has answered questions."

Since the bombings, she has been represented by two malpractice and personal injury lawyers from Rhode Island, where her family lives. They announced a third lawyer from New York, Joshua Dratel, who has experience in national security and terrorism cases, has been added to the team.

The goal, they said, is to ensure "that Katie can assist in the ongoing investigation in the most constructive way possible."

The lawyers have said in the past that the allegations against her husband and brother-in-law came as an "absolute shock" to her.

She gave up a DNA sample so authorities could compare it to female DNA on a bomb remnant. It was not a match.

Investigators believe the bombs were assembled at the home where she lived with Tamerlan and their child.

Russell converted to Islam after she met her future husband in 2009. She dropped out of college, got married and had a baby and had been working as a home health aide to support the family.

Her husband was killed during a firefight with police, and she instructed the medical examiner's office to release his body to his relatives. The family has not been able to find a cemetery willing to bury him.